Skills for Access

Conditions exist that reduce a person's sensitivity to visual or auditory information. Photosensitive epilepsy refers to a form of epilepsy where seizures can result from exposure to flickering or flashing light. While the National Centre for Epilepsy estimate 300,000 people in the UK have epilepsy, and that one in 20 people are likely to have a seizure, it's estimated that only around 5 per cent of people with epilepsy are photosensitive.

Natural and artificial light sources can both trigger seizures, but television is generally the most common trigger. There appears not to be any evidence to suggest that the use of a cathode ray tube (CRT) television or computer monitor on its own presents any risk to people with photosensitive epilepsy, but flashing or strobe-effect content displayed on the screen is obviously a potential trigger.

Various types of seizure may result from by flickering light, ranging from a brief jerking of limb(s) to a longer period of convulsion, possibly accompanied by temporary breathing problems. Factors in the severity of the seizure include brightness of the light source, frequency of flashing, and size of field of vision exposed to the flashing.

Much rarer is a sensitivity to sound of a particular frequency or volume. Hyperacusis is a condition that has been defined as "a collapsed sensitivity to sound", with a primary effect of sounds seeming extremely - and unpleasantly - loud.